Film holder



i5, w52 P. D. MERRILL 2,603,07

FILM HOLDER Filed Dec. 6, 1948 mwa/WMM' 147' T OZNEKS.

Patented July 5, 1952 'ortica' FILM nomen l Patterson Davy Merrill,South Bend, Ind. Application December 6, 1943, Serial No. 63,700

Claims.` (MAW-152) l This invention relates to improvements in lmholders, and more particularly to a holder for films of the typecommonly known as color transparencies, which aremounted in a projectorto be viewed.

The primary object of this invention is to provide an inexpensive lmholder in which films may be mounted easily and quickly to be fullyprotected, which is small in size, thin in crosssection, and light inweight.

A further object is to provide a film holder of this character which isdustproo-f and which is characterized by continuous seals at the lockingjoint between the sections thereof and at the inner perimeter of bothsides thereof.

A further object is to Iprovide a device of this character which isresilient and which friction-y ally grips a pair of transparent platesbetween which a lm is mounted so that said plates and film will notslide in the holder.

A further object is to provide a lm holder of this character havinginner marginal gripping portions or jaws,` normally of substantiallyfrusto-pyramidal form and flexible to compensate and accommodatevdifferences in thickness of the film and protective glass platesinterposed therebetween.

A further object is to provide a device of this character which isformed of two separatable parts resiliently interlocked, whoseconfronting faces at their margin outwardly of said interlock are spacedapart to facilitate insertion of a knife or other edged member which maybe used to effect separation of the parts.

Other objects will bejapparent from the following specification.

In the drawing:

Fig. 1 is a face view of the film holder with parts thereof broken away.taken on line I--I of Fig. 3.

Fig. 2 is an enlargedvsectio-nal view taken on line 2 2 of Fig. 1, andillustrating the parts in their operative assembled lpositionpreparatory to interlocking thereof.

Fig. 3 is a view similar to Fig. 2 and illustrating the parts of the lmholder in operative interlocked position.

Referring to the drawing which illustrate-s the preferred embodiment ofthe invention, the numeral II) designates a film, such as a colortransparency to be mounted in the film holder, and the numeral I2designates glass plates or panels positioned upon opposite sides of andin face engagement with the film I0. The numeral I 4 designates myimproved `llm holder, This 2 improved film holder is preferably formedof a synthetic resin, such ascellulose acetate, styrene, vinyl chloride,acrylic or the like. Itwillbe understood that the` resins enumeratedherein cited are illustrative of the resins whichmay be employed andthat anyk otherresin found suitable may be used.

The film holder compri'sestwo ,parts in the nature of rim members andidentified respec-vl tively -by the numerals I6 and I8. Both of. theserim members are molded from suitable synthetic resin material andarepreferably of vrectangular' shape although they may be'fabricated in anyother shape found suitable. The rim parts IE and i8 are preferably ,ofthe'same size and shape in outline and preferably have the same innerperimetral dimension so that a sight opening 20 is provided throughwhich light from a projector (not shown) may pass to throw the imagelborne by the film upon a screen'in a manner well unu derstood in theart. y Y

The rim member I6 has lan inner marginal anger22 of inwardly taperingcross-.sectional shape and of reduced thickness to render the same moreflexible than the remaining 'portion-s of said rim member. The Ainnerflangeportion 22 is of substantially frusto-pyramidal form and inclinedinwardly at a slight angle relative to the plane of the member IB. Theflange portion 22 extends continuously at the inner marginv of themember i6 and its Awidth is substantially one-half the width of y'saidmember I6. At 'its outer margin the member I6 has a continuousperpendicularly inwardly projecting thickened flange portionZ', hereshown Aas of a width Ysubstantially one-quarter of the width 'of themem-'- ber i6 and of a depth greater thanthe spacing of the inner edgeof the flange 22 from the outer surface of the member It. `The innerface of the flange portion 24 has a shallowrib 2Brformed thereinadjacent its free edge and .preferably defined by an outer face portion28 and an inner face portion 30, which face portions converge, and eachof which extends at an angle of substantially 30 degrees from theremaining `inner face portions 32 of the ange 2 4. The Width of the rib26 is less than one-half Vthe depth of said flange. The'part I6 ispreferably molded so that its flanges 22 and 24 and its rib 426areformed integrally. v

The rim member I 8' has an inner marginal flange 35i of substantiallythe same size, shape and construction as the ange 22 of the member IB. Alaterally inwardly projecting thickened flange portion 36 ofvsubstantially rectangular cross-section extends continuously around therim member I8. The outer perimetral dimension of the flange 36 is ofsmaller dimension than the inner perimetral dimension of the flange 24so as to fit freely within said flange. The inner perimetral dimensionof the flange portion 36 is greater than the outer perimetral dimensionof the film Il! and the plates I2, which latter `are of substantiallylarger dimension than the dimension of the sight opening 20. The outermarginal portion 38 of the part I8 is of substantially the samethickness as the flange 24 of the member I 6, but portion 38 may beomitted if desired. The outer surface of the flange portion 36 includesan inclined surface 40 complementary to the surface 28 of the member I6,and a second inclined surface 42 complementary to the surface 30 of themember I6. These two inclined surfaces 40 and 42 cooperate to define aperimetral rib 44 extending around the outer surface of the flange 36.The perimetral dimension of the rib 44 at its crest between the inclinedsurfaces 40 and 42 thereof is substantially equal to the perimetraldimension of the inner face 32 of the flange 24 of the member I6. Thefaces 28, 30 and 42 are preferably of substantially the same length andthe face 40 is of greater length, whereby the free or outer end of theflange 36 may pass into the member I6 clear of the rib 26. The rib 44 isformed intermediate the depth of the flange 36.

In the use of the device the film I is positioned between the glass orother transparent plates I2 and this assembly is then inserted into thepocket of the member I8 defined by the flange 36. The member I6 is thenapplied over the member I8 to the position illustrated in Fig. 2. Theribs 26 and 44 are so positioned with respect to the depth of the innermarginal flanges 22 and 34 that the inner edges of said flanges willbear against the outer faces of the transparent plates I2 when the faces28 and 40 come into engagement. Thereupon the parts I6 and I8 arepressed together, causing the rib 26 of the member I6 to slide over therib 44 and to anchor therebehindin the position illustrated in Fig. 3,with the surface 30 of' the rib 26 in continuous face engagement withthe surface 42 of the rib 44. The member I6, being formed of a plasticmaterial having at least a measure of resilience in the thin sectionsemployed in this device, has a spring action accommodating theinterlocking of the ribs 26 and 44 as shown, and also accommodatingflexing of the inner marginal flanges 22 and 34 to the positionillustrated in Fig. 3 ln which the inner edges of said flanges 22 and 34have continuous engagement with the outer surfaces of the transparentplates I2. The flexing of the inner marginal flanges 22 and 34 distortssaid flanges slightly, and, by reason of the resilient character of thematerial, a firm spring grip occurs acting in a manner to separate thetwo parts I6 and I8 but being prevented from separating said parts bythe face engagement of the ribs 26 and 44. This spring action serves tohold the faces 28 and 42 in continuous firm face engagement, thusconstituting a dust seal at the outer margin or joint between the twoparts I6 and I8. The parts are preferably so constructed that when theyare interlocked, as illustrated in Fig. 3, a slit or opening 46 isprovided between the confronting surfaces of the flange 24 of the memberI6 and the part 38 of the member I8. This slit is of very smalldimension but is suflicient to permit the insertion therein Of a 4 bladewhich can be manipulated by turning the same about its longitudinal axisat an inclination to the planes of said confronting surfaces and to anextent to facilitate the release of the interlocking engagement betweenthe ribs 26 and 44.

As an illustration of the dimension of the parts, the thickness of theflange 24 of member I6 and of the part 38 of the member I8 isapproximately one-sixteenth of an inch; the thickness of the part I8 atthe flange 36 is approximately .107 inch; and the thickness of theflanges 22 and 34 adjacent their inner edges is approximately .01 inch.The height of each of the ribs 26 and 44 from the surfaces from whichthey project is approximately .005 inch. The total clearance between theface 32 of the flange 24 and the outer face of the flange 36 outwardlyof the rib 44 is approximately .01 inch. The major dimension or lengthof the holder is approximately two and three-quarters (2%) inches, andthe sight opening at the major dimension of the device is approximatelytwo and one-eighth (2l/8) inches. The total over-all width of each ofthe rim members between their outer marginal edges and the inner edgedefining the sight opening 20 is approximately five-sixteenths of aninch. These dimensions are cited for purposes of illustration only, andit is understood they are not limiting.

It will be apparent from the foregoing that a continuous perimetraldustproof seal is afforded between the ribs 26 and 44, and between theinner edges of each of the flanges 22 and 34 and the plate I2 engagedthereby. Consequently, there is no possibility that any dust or dirt canaccumulate within the holder or contact the film I0. The friction gripafforded by the resilience of the flanges 22 and 34 holds the lock atthe ribs 26 and 44 effective at all times and imparts sufficientpressure upon the plates I2 to insure that neither said plates nor thefilm I0 may slip or be displaced from its proper position. If anyirregularities in the thickness of the glass plates occur, theflexibility of the ribs 22 and 34 is suilicient to compensate for themand at the same time maintain the continuous dust-tight engagement.These features combined produce a holder which meets satisfactorily allconditions and requirements of use of such a film holder, it beingobserved that the film holder protects the outer surfaces of the glassI2 as Well as the film I0 by reason of the inset position of thesurfaces of said plates relative to the planes of the outer surfaces ofthe parts I6 and I8. The device is light in weight and, by reason of itsmolded form, can be produced inexpensively.

While the preferred construction of the device has been illustrated anddescribed herein, it will be understood that changes may be made thereinwithin the scope of the appended claims without departing from thespirit of the invention.

I claim:

1. A film holder adapted to mount a pair of transparent panels and afilm interposed therebetween, comprising a pair of substantially flatresilient plastic parts of substantially the same perimetral dimensionand each having a central sight opening, one of said parts having anintegral laterally projecting flange extending continuously at its outermargin, the other part having a continuous integral laterally projectingflange spaced from its outer margin a distance greater than thethickness of said first flange, perimetral ribs formed integrally onsaid flanges respectively at the inner perimeter of said first ange andat the outer perimeter of said second iiange, said ribs being of suchdimension and location as to interengage with a snap action tocontinuously lock said parts together, the inner marginal portion ofeach part being of reduced thickness and inclined inwardly relative tothe plane of said part and adapted to be flexed to -continuously gripsaid panels and iilm therebetween.

2. The construction dened in claim 1, wherein said ribs are defined bycomplementary angularly disposed converging faces with one thereofbearing ilat against a face of the other rib when said parts areinterlocked.

3. A lm holder adapted to mount a lm interposed between transparentplates, comprising a pair of substantially at rectangular plastic rimmembers having similar'central openings smaller than said plates, eachrim member having an inner marginal portion of reduced thickness andfrusto-pyrarnidal form, the outer marginal portion of one rim memberhaving a thickened ilange whose inner face has a continuous perimetralrib adjacent its free edge, the other rim member having a thickenediiange tting with clearance within the first marginal iiange and whoseouter face has a continuous perimetral rib spaced from its base, the,`perimetral dimension of the crest of said iirst named rib being slightlyless than the perimetral dimension of the crest of said last named ribto accommodate interlocking of said rim members at said ribs with a snapaction, said ribs being so positioned relative to the planes of theedges of said frusto-pyramidal portions as to flex said frusto-pyramidalportions outwardly when said rim members are interlocked with said lrnand plates interposed therebetween, whereby said ribs are held incontinuous sealing engagement and each frusto-pyramidal portion is heldin continuous sealing engagement with one of said plates.

4. The construction defined in claim 3, wherein said ribs havecomplementary flat frustopyramidal sealing face portions, theconfronting surfaces at the outer margins of said rim members beingslightly spaced when said last named face portions are in interlockedsealing engagement.

5. A lm holder comprising a pair of parts adapted to clamp therebetweenan insert including a film and a transparent plate in face engagement,said parts having central openings smaller than said insert,telescopically intertting perimetral flanges carried by said parts, theouterl perimetral dimension of said telescoped flange being smaller atmouth than the inner perimetral dimension of said telescoping flange atits mouth whereby said parts interiit loosely when initially appliedtogether, a perimetral internal ridge carried by said telescoping angeadjacent to its mouth and defined in part by a tapered surface facingits mouth, and a perimetral external ridge carried by said telescopedflange intermediate its width and defined in part by a tapered surfacefacing its mouth, the major perimetral dimension of saidlast named ridgebeing slightly less than the smallest perimetral dimension of said firstnamed ridge, whereby said ridges pilot said parts into register uponinterengagement of said tapered surfaces and interlock with a snapaction when said ridges are pressed past each other. e

PAT'I'ERSON DAVY MERRILL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,394,675 Frechette Oct. 25, 19212,176,283 WhitefordV Oct. 17, 1939 2,186,643 VKaplan Jan. 9, 19402,292,312 Wittel et al; l Aug. 4, 1942

